(1) Field of the Invention
The present invention relates to an electric recording material and an electric recording process. More particularly, the invention relates to an electric recording material comprising a substrate and an electrically conductive layer formed at least in the surface portion of said substrate, said electrically conductive layer containing a basic salt of divalent tin or tin (II) hydroxide dispersed in an electrically conductive medium, and to an electric recording process using this electric recording material.
(2) Description of the Prior Art
As the conventional electric recording process, there are known (A) an electrolytic recording process comprising injecting hetero ions into a recording material, (B) an electrolytic recording process utilizing discharge of ions at an electrode falling in contact with a recording material, (C) an electrolytic recording process utilizing oxidation (anode oxidation) or reduction (cathodic reduction) on the surface of an electrode falling in contact with a recording material, (D) a recording process utilizing local change of the pH on the surface of a recording material falling in contact with a recording material, and the like. Among these known processes, the cathodic reduction process is advantageous in that consumption of an electrode stylus to be used for recording can be maintained at a lowest level.
As the electric recording material that can be used for the recording process utilizing cathodic reduction, there are known a recording material formed by coating dispersion of a reducible silver salt such as silver behenate in an electrically conductive medium such as an electrically conductive resin on an appropriate substrate, and a recording material formed by coating a dispersion of 2,3,5-triphenyltetrazonium chloride in an electrically conductive medium on an appropriate substrate. In a recording material of the former type, when the silver salt in the electrically conductive medium falls in contact with a cathode stylus and an electric current is applied thereto, it is reduced and black metallic silver is precipitated to form an image, and in a recording material of the latter type, the tetrazonium in the medium is cathodically reduced to form an image of a formazan dye.
These known recording materials, however, are still insufficient and defectice. For example, in the recording material of the former type, by cathodic reduction metallic silver is precipitated ordinarilly in the form of very fine particles, and therefore, it is difficult to form an image having high contrast and high density. Further, since an expensive silver salt must be used, the cost of the recording material becomes high. In case of the recording material of the latter type, in general, the resulting image is reddish and the image density is low. Further, fastness, e.g., light fastness, is poor and preservability is insufficient.